Hypersensitivities

Question 1

Hypersensitivity?

Answer 1

Any Immune response against a foreign antigen exaggerated beyond the norm

Question 2

What are the four types of hypersensitivity?

Answer 2

Type 1 (immediate)
Type 2 (cytotoxic)
Type 3 (immune complex-mediated)
Type 4 (delayed or cell-mediated)

Question 3

Type 1 hypersensitivity

(Immediate)

Answer 3

-results form the release of inflammatory molecules in response to an antigen

-develops soon after exposure to an antigen

-commonly called allergy

-the antigens that stimulate it are called allergens

Question 4

Type 1 hypersensitivity

(Immediate) contd.

Answer 4

-roles of degranulating cells in an allergic reaction
-degranulation occurs after cells are sensitized
*mast cells
*basophils
*eosinophils

-degranulation releases histamine, kinins, proteases, leukotrienes, and prostaglandins

Question 5

Type 1 hypersensitivity

(Immediate) contd—

Answer 5

Clinical signs of allergic reactions
-usually mild
-site of reaction depends on portal of entry
-small inhaled allergens may reach lungs and cause asthma
-some foods contains allergens
*may cause diarrhea and other GI signs and symptoms
-local skin inflammation may produce hives or URTICARIA

Question 6

Immune components involved in urticaria ?

Answer 6

Granulocytes (basophils?)

IgE

Inflammatory chemicals

Question 7

Type 1 hypersensitivity can cause?

Answer 7

-acute anaphylaxis or anaphylactic shock

Question 8

What can treat anaphylaxis?

Answer 8

Epinephrine

Question 9

How to diagnose type 1 hypersensitivity ?

Answer 9

High levels of IgE against specific allergen

Skin test

Question 10

Prevention of type 1 hypersensitivity

Answer 10

-avoid allergens
-eliminate suspected foods with allergens from diet
-immunotherapy
-administer drugs that counteract inflammatory mediators
-treat asthma with corticosteroid and bronchodilator
-epinephrine neutralizes many mechanisms of anaphylaxis

Question 11

Type 2 hyper sensitivity is what ?

(Cytotoxic)

Answer 11

Results when cells are destroyed by an immune response

(Blood cells destroyed)

Question 12

What type of hypersensitivity is a component of many auto immune diseases?

Answer 12

Type 2, cytotoxic hypersensitivity

Question 13

2 examples of type 2 hypersensitivity

(Cytotoxic)

Answer 13

Destruction of blood cells following incompatible blood transfusion

Destruction of fetal red blood cells in hemolytic disease of the newborn

Question 14

The main concept of type 2 (cytotoxic) hypersensitivity

Answer 14

Antigens and antibodies from blood transfusion cause destruction of rbc due to antibodies to foreign blood antigens

Question 15

How many humans are rh+?

Answer 15

85%

Question 16

What is administered to pregnant woman who are rh- with rh+ baby ?

Answer 16

RhoGAM

Question 17

Type 2 hypersensitivity drug induced cytoxic reactions That can produce what disease ?

Answer 17

-immune thrombocytopenia purpura
-agranulocytosis
-hemolytic anemia

Question 18

Type 3 (immune complex- mediated) hypersensitivity ?

Answer 18

-caused by formation of immune complexes

Question 19

Type 3 HS. (Immune complex-mediated)

Can cause what type of localized reactions ?

Answer 19

Hypersensitivity pneumonitis

Glomerulonephritis

Question 20

Type 3 HS. (Immune complex-mediated)

Can cause what type of systemic reactions ?

Answer 20

-systemic lupus erythmatosus

-Rheumatoid arthritis

Question 21

Hypersensitive pneumonias
(Type 3 immune complex- mediated HS)

Answer 21

Inhalation of antigens stimulates antibody production.

Subsequent inhalation of same antigen results in formation of immune complexes, activates complement

Question 22

Glomerulonephritis

(Type 3 immune complex- mediated HS)

Answer 22

Immune complexes in the blood are deposited in glomeruli

Damage to glomerular cells impedes blood filtration

Kidney failure and death

Question 23

Rheumatoid arthritis

(Type 3 immune complex- mediated HS)

Answer 23

Immune complexes deposited in the joint
-results in release of inflammatory chemicals
-joints break down and distort

Trigger not well understood
Treated with anti inflammatory drugs

Question 24

Systemic lupus erythematosus

(Type 3 immune complex- mediated HS)

Answer 24

Autoantibodies against DNA result in immune complex formation

Many other antibodies can also occur
-against rbc, platelets , lymphocytes, muscle cells

Trigger uknown

Immunosuppressive drugs reduce autoantibody formation
Glucocorticoids reduce inflammation

Question 25

Immune components involved with systemic lupus erythmatosus

Answer 25

-autoantibodies (lupus)
-Ag-ab-complement complex

Question 26

Type 4 (delayed or cell-mediated) HS

Answer 26

*involves T cells

-inflammation 12-24 hr after contact with certain antigens

Delay reflects the times it takes for macrophages and T cells to migrate to and proliferate at the site of the antigen

Question 27

Type 4 (delayed or cell mediated) HS
CAUSE

Answer 27

-The tuberculin response
-allergic contact dermatitis
-graft rejection

Question 28

Type 4 (delayed or cell -mediated) HS

Graft rejection ?

Answer 28

-Rejection of tissues or organs that have been transplanted
-grafts perceived as foreign by recipient undergo rejection
-immune response against foreign MHC on graft cells
-rejection depends on the degree to which the graft is foreign to the recipient
-based on type of graft

Question 29

4 types of grafts

Answer 29

Autograft- from same donor to itself (rat to self)
Isograft- genetically identical sibling or clone (rat to cloned rat)
Allograft- genetically different member of same species (not related) (rat to different rat)
Xenograft- different species (rat to cat)

Question 30

Type 4 (delayed or cell mediated ) HS

Graft versus host disease usually happens?

Answer 30

In bone marrow

Question 31

Type 4 (delayed or cell mediated ) HS

Graft versus host disease

Answer 31

-donated bone marrow cells regarded patient cells as foreign

-donor and recipient differ in MHC class 1 molecule
Grafter T cells attack recipient tissues

-donor and recipient differ in MHC class 2 molecules
Grafted T cells attack the host antigen presenting cell

-immunosuppressive drugs can stop graft versus host disease

Question 32

Type 4 (delayed or cell mediated ) HS

Donor recipient Matching and tissue typing

Answer 32

MHC compatibility between dont and recipient is difficult because of a height degree of variability / specific to each individual

-the more closely the donor and recipient are related, the smaller differences in MHC

-parent or sibling preferable

Question 33

Type 4 (delayed or cell mediated ) HS

Immunosuppressive drugs are important to transplantation success.

Answer 33

Classes of immunosuppressive drugs
-glucocorticoids
-cytotoxic drugs
-cyclosporine
Lymphocyte-depleting therapies

Question 34

Type 1 HS causes

Answer 34

-asthma (use bronchodilator)
-GI issues (avoid food)
-urticaria (hives)-(epinephrine)

Question 35

Type 2 HS causes

Answer 35

(Blood related)

-immune thrombocytopenia purpura (low platelets)
-agranulocytosis (low wbc)
-hemolytic anemia (low Rbc)

Question 36

Type 3 HS causes

Answer 36

(Localized)
-hypersensitivity pneumonitis (lungs inflames)
-glomerulonephritis (inflammation/damage to glomerulus/kidneys)

(Systemic)
-systemic lupus eruthematosus (immune system attacks own tissues/organs cause inflammation )
-rheumatoid arthritis (immune system attacks own cells, mainly joints )

Question 37

Type 4 HS causes

Answer 37

-tuberculin response (tb test)
-allergic contact dermatitis (inflammation of skin)
-graft rejection (immune system attacks donated tissue/organ)

Question 38

Type 4 HS causes contd.

Answer 38

-Graft vs host disease (donated bone marrow response)
-donor-recipient matching and tissue typing

Question 39

Classes of immunosuppressive drugs

Answer 39

-glucocorticoid
-cytotoxic drugs
-cyclosporine
-lymphocyte-depleting therapies